Care guide · Freshwater shrimp

Sulawesi cardinal shrimp

Caridina dennerli

Photo: DirkBlankenhaus / Wikimedia Commons, CC BY-SA 3.0; resized. Photo: DirkBlankenhaus · Source · CC BY-SA 3.0resized and compressed for responsive web delivery; original file 1024 × 714 px

The Sulawesi cardinal shrimp (Caridina dennerli) is a small, striking red freshwater shrimp from Lake Matano on Sulawesi. It grazes on hard surfaces and needs a warm, stable aquarium with clean water and established growth. The water values shown here are aquarium recommendations from a specialist source, not experimentally proven biological limits. A reliable numeric minimum tank volume and universal minimum group size were not established, so neither is presented as a fixed number. The species was assessed as Critically Endangered in 2018, while later field work reported it again at several localities. Choose only shrimp with traceable captive-bred provenance, and never release aquarium animals or water into natural waterways.

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At a glance

Temperature: 27–30 °C
pH: 7.5–8.5
GH: 7–10 °dGH
Diet: Omnivore
Adult size: Up to 2 cm
Temperament: Peaceful

About this species

Caridina dennerli was scientifically described by Kristina von Rintelen and Yixiong Cai in 2009. It is an atyid shrimp in the genus Caridina. Its deep red colour and pale spots help identify the cardinal shrimp, but trade labels or colour patterns alone do not establish provenance or a breeding line. A specialist aquarium profile gives an adult length of about 1.5–2 cm. The taxonomic paper also reports carapace measurements for examined specimens; carapace length is not the same as total body length. We do not convert one measurement into the other.

Natural habitat

The original description records the species from Lake Matano in South Sulawesi, Indonesia. It is endemic: the documented natural range is in that lake. Specimens were found on hard substrate among stones and boulders, from shallow water to around ten metres deep. In an aquarium, hard surfaces and crevices therefore provide a more useful structure than a bare, soft bottom. Algal growth and biofilm on rock provide natural grazing surfaces. A home aquarium cannot reproduce the ecology of a deep ancient lake; use habitat records to guide layout, not as proof of every desired water number.

Aquarium and layout

A dedicated species aquarium is the cautious choice. The specialist aquarium source advises against keeping it with fish. Build stable rock structures with crevices and plenty of surface for biofilm to develop. At the same time, maintain clean, oxygenated water and guard the filter intake so small shrimp cannot be drawn in. Let the aquarium mature biologically before adding animals; a newly set-up sterile tank provides little natural grazing. The sources reviewed do not firmly support a numeric minimum volume or exact minimum group count. Choose a setup for stable water chemistry, practical maintenance and room for a group, rather than displaying a falsely precise minimum.

Water conditions

The specialist aquarium profile recommends 27–30°C, pH 7.5–8.5 and GH 7–10 dGH. These are practical husbandry recommendations, not experimentally established lower and upper biological limits. Keep conditions stable; abrupt changes in temperature, minerals or pH can stress shrimp. Ask the breeder about the actual water in which the colony was raised and acclimate new animals gradually. No exact KH or TDS target is given because the sources checked do not establish a sufficiently reliable universal aquarium range for those measures. Measure both tank and replacement water, and avoid contamination by metals or other harmful substances.

Behaviour and group size

Cardinal shrimp move across stones and other firm surfaces, grazing on growth there. A calm group with several grazing areas is a more cautious arrangement than a tank where fish create continual food competition or predation pressure. The specialist aquarium source recommends a larger group but does not establish a firm minimum, so no number is shown. Take their small body size into account during maintenance: shrimp and young can disappear among rockwork, filter sponge and plant debris. Move hardscape carefully and inspect siphoned water before discarding it.

Feeding

In the lake, this shrimp grazes on algae growing on stones. In the aquarium, established biofilm is therefore an important part of the food available. The specialist husbandry source mentions supplementary shrimp food, tablets, spirulina and small Artemia nauplii. This is general diet guidance, not evidence that a particular brand product is complete or necessary; no product link is added here. Offer small amounts, check that the shrimp can reach the food and remove leftovers before they affect water quality. Keep grazing surfaces available rather than trying to compensate for a lack of growth with unlimited dry food.

Breeding

Caridina dennerli is a freshwater species. The aquarium source says reproduction in captivity is possible, but also notes that species-specific breeding conditions are not established well enough for a fixed protocol. We therefore give no guaranteed incubation period, clutch size or yield. If juveniles appear, protect filter intakes, provide fine shelter and maintain accessible biofilm surfaces. Keep water stable and avoid maintenance that can siphon up small animals. A breeding result in one aquarium does not prove that the same settings work everywhere. Any commercial or conservation claim should match documented provenance and records.

Keeping with fish

A species-only aquarium is the cautious choice for this specialist shrimp. The specialist husbandry source advises against fish tank mates. We found no reliable species-specific trial confirming any fish as a safe pairing, so no fish is listed as suitable. Even small fish may eat juvenile shrimp or compete for food; the latter is a general risk assessment, not a demonstrated trial for every fish species.

Keeping with other invertebrates

The Matano rabbit snail (Tylomelania patriarchalis) is the only conditional pairing assessed. Both species are known from Lake Matano, but they do not prefer the same substrate: the shrimp is recorded on rocks, while the snail is chiefly associated with sand and mud. Sharing a lake does not prove a successful aquarium pairing. Treat this as a cautious, experimental possibility only, with separate rock and sand zones, adequate feeding and close observation; separate the animals if stress or food shortage appears.

Exoskeleton, shell and minerals

Like other shrimp, Caridina dennerli moults as it grows. A shed exoskeleton is not, by itself, a disease and may be eaten by the shrimp. The sources do not provide a species-specific mineral recipe or dose for moulting. Keep water chemistry stable, avoid sudden changes in temperature or mineral content, and do not add calcium or mineral products without an identified need. Provide crevices among the stones where a freshly moulted shrimp can retreat.

Possible problems

The main concerns are unstable warmth, pollution, too little mature biofilm and an unguarded filter intake. The warm husbandry range calls for adequate oxygen and a mature, well-maintained aquarium. If the shrimp behave abnormally, check ammonia/ammonium, nitrite and temperature, and remove decaying food. Do not diagnose disease from a colour change alone: stress, moulting and water problems can produce similar signs. Ask an experienced shrimp keeper for help if the problem continues.

Sources & review

This care guide draws on several specialist sources and was last checked on 17 October 2026.

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